The present invention relates to a door lever assembly that is easily assembled and resists damage or vandalism and, more specifically, to a single or double door lever assembly being fitted together without use of machined forgings or castings.
Typically, conventional housings for door levers are constructed from machined forgings or casting. Mounting studs for attachment to the door in such conventional housings consist of male threads that mate with a casting or forging using drilled or tapped holes cut through the housing. Alternatively, milled undercuts in a housing are used to provide spring seats, with containment walls retaining internal sliding members for lifting vertical rods connected to door latches or other manipulable lock elements. Drilled or counterbored holes in the forging are commonly required in this type of milled forging to receive the key cylinder.
Unfortunately, the necessity for drilling or machining these types of conventional housings greatly increases time and cost of door lever assembly. Substantial effort is required to machine and/or drill trim housings to accept and hold components of a door lever assembly. In addition, the need for auxiliary fasteners for attachment of door lever components to a trim housing increase cost and time required for assembly of a door lever assembly. What is needed is a low cost trim housing that does not require auxiliary fasteners, does not require additional drilling or machining for use, and can be constructed from a deep drawn metal stamping using welded studs instead of traditional threaded fasteners to secure door lever assembly components.
Such a fastenerless trim assembly can be used to replace conventional door levers having a fixed lock position that are subject to damage by vandals or those seeking unauthorized entry into commercial or public buildings. A conventional locked door lever extends outward in a substantially horizontal position and can be impacted with hammers or other devices to break the lever or shatter lock components. In addition, it is sometimes possible to use the weight of a person seeking entry to downwardly force a door lever and break the lock mechanism. To partially overcome this problem, certain door levers are designed to have shear pins or other elements for designed failure that break and render the lever mechanism inoperable after application of undue force.
For example, a conventional door lever typically has a trim housing machined or drilled to accommodate a key cylinder lock above a rotatable lever handle that is operably connected to a door latch mechanism. The lever handle is permanently pinned to a shaft that extends inward to engage an eccentrically configured cam. The cam can be rotated to upwardly move a slider plate that is in turn connected to a lift arm. Movement of the lift arm in turn causes movement of vertically directed rods that are connected to retract a door latch. Locking this assembly simply requires rotation of the key cylinder to engage a blocking slide known as a trim lock tumbler that prevents movement of the lift arm, and consequently fixes the slider, cam, shaft, and door lever in a fixed and locked position.
However, with this type of assembly the door lever handle is fixed (in its locked position) to extend horizontally outward. To prevent permanent damage to the lock mechanism, a shear pin is provided to connect cam and the shaft. Application of excessive torque forces to the lever handle causes failure of the shear pin, effectively disconnecting the lever and attached shaft from the remaining elements of the door lever assembly. Although this protects the remaining lock elements from further damage, it does require removal of the trim housing and replacement of the shear pin to restore lever function.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.